the unanswered problem?

[kewelljewell]

i have read over many posts and still there is no real answer concerning the audio problems when encoding a dvd. im going to explain everything i have done so that the best advice can be offered to me.

i have tried using virtual dub, goldwave and avi2wav, all of these have produced the exact same problem, when i encode the file in tmpgenc, it results in about one and a half second out of sync problem. it isnt a gradual build up, as soon as i play the converted mpeg-2 file, its out of sync right from the beginning. why is this happeneing to so many people and is there no answer? im desperate to find out as it is halting my dvd making process. cheers for any help offered, would be much appreciated.

Mark

[j1d10t]

When you encode which file? The video, the audio, or both? If you are converting the audio separately (using TMPGEnc), try converting it with the video. If you are converting the video with TMPGEnc, and the audio with some other program, try inserting a silence before the audio, or trim a little off the front (if the audio plays after the video) before you convert it to the final format...

There are many things you can do to correct this problem. You just have to play around with it, and see which works best for you.

[Ziffelpig]

If your audio is out consistently, you can try this, download womble mpg-vcr,install and open your mpeg. Then select--->Tools---->Mpeg systems demultiplexer and demux your file.Then open---->Tools ---->Mpeg systems multiplexer , and load your demuxed video and audio, choose the Mpeg2 program stream, and give your output file a name. Click on the AV-Sync and adjust to the approximate time you are out,(you can change the offset value to increase the time period) then click done and save your file.
You may have to experiment a couple of times to get it right but it has always worked for me when the audio was out of sync from the beginning of the movie.

[Gazorgan]

When you strip out the audio, is it the same length as the Video?

Also, when you strip out the audio, what is the delay? You simply may have an audio stream with an unusual delay. Some Audio has zero, or maybe 128 milliseconds (common for AC3).

To fix a 'fixed audio delay' you can open the WAV in a good editor like Soundforge and pad the beginning by the amount your off, or alternately cut off some of the beginning. Either way you need to do the opposite to the end of the WAV to keep it the same length as the video.

As to why it's happening? People don't want you re-encoding 'Their Work'. That's one reason people use VBR mp3 audio(besides the space saving), the average user can't convert it. Download a better class of video?

[bottle-necked]

kewelljewell, all the answers you have gotten so far are excellent and from people that has been doing video for a long time. I agree with their solutions but here is how I do it: ok

I open my AVI file in VirtualDub and click 'File' then 'File Information' and get the 2 numbers I need for my correction process. 1 for video length and 1 for audio length then I can calculate the offset value.

For instance say I have an AVI file that the 'VIDEO STREAM' length is 0:18:34 long. The 'AUDIO STREAM' length is 0:17:86 in length. I would subtrace the audio from the video length (18.34-17.86) and get .48 (480ms).

I open this AVI file in TMPGEnc for encoding to MPEG, click Settings, Advanced, double click 'SOURCE RANGE' and type in my 480ms in 'Audio Gap Correct' box except I must make it a minus 480 (-480). Then encode the file like normal.

There are many ways to correct audio offset, as explained by those above, but this is the easiest way I have found 'for me' to repair it. My ATI and Creative cards seem to always have an offset value around 400-500ms when I capture in AVI. I'm getting used to correcting it. lol

This method will correct audio offset but it will not repair progressive sync issues.

(While in VirtualDub and File Information I always check the framerate of my AVI files also. If the framerate is off you will need to take other actions to repair the sync issue.)

Good luck.

[andkiich]

Another solution to look at is the authoring programs. I use DVD-Lab and it has an option to shift the audio to fix sync problems. That might work for you as well.

[MrMungus]

Another thing to consider is your source tape. I was having problems where a really bad tape was causing files to be created that TMPGEnc Author couldn't handle. In other words, the file played fine after capturing (perfect lip synch) but after being processed into VOB files, audio synch was lost.

[kewelljewell]

thanks a lot guys, all brilliant advice and im gonna check out a few things that you've told me. just to let you know, the source files are hdtv xvid files, they have been downloaded.

This is to j1d10t. im using the compressed template for encoding up to six hours of dvd using tmpgenc. when i convert the audio using virtual dub, i can tell its around 1 and a half seconds off before its even been encoded! i dunno why this is, i tried different files (all hdtv though) and its the same for them all. any ideas?

to gazorgan, the audio is around 1 second off, ie the video is one second longer, but surprisingly sometimes the same length. when i open my avi file in virtual dub, an error message also appears about vbr audio stream and how it needs to be corrected to cbr? i read to just ignore this but it must mean something.

Thanks for all your help so far, it has all been helpful, you's are increasing my knowledge of all this anyway so thanks for that!